Regularly taking cold showers imposes a small amount of stress on your body, which leads to a process called hardening. This means that your nervous system gradually gets used to handling moderate levels of stress.
Cold showers wake your body up, inducing a higher state of alertness. The cold also stimulates you to take deeper breaths, decreasing the level of CO2 throughout the body, helping you concentrate. Cold showers therefore keeps you ready and focused throughout the day.
Scientific studies have found that taking a cold shower increases the amount of white blood cells in your body. These blood cells protect your body against diseases. Researchers believe that this process is related to an increased metabolic rate, which stimulates the immune response.
It takes a strong mind to endure the cold for extended periods of time. By incorporating cold showers into your daily routine, you are strengthening your willpower, which benefits many aspects of (your) daily life.
Research has shown that cold showers (and exposure to cold in general), in addition to increasing metabolic rate directly, stimulate the generation of brown fat. Brown fat is a specific type of fat tissue that in turn generates energy by burning calories. Cold showers, then, are an effective tool for weight loss.